It is known that particularly potassium metal can be produced by thermochemical processes (German Patent Publication No. 19 32 129). The starting compounds used for that purpose are mainly potassium halides, potassium carbonate or potassium hydroxide and the reducing agents used are mainly coal, calcium carbide, aluminum, magnesium, silicon or ferrosilicon.
In the process disclosed in U.S. Pat. No. 2,480,655, potassium metal is produced by a reduction of molten potassium compounds by means of sodium metal. Such processes can be carried out only at high temperatures in the range from 500.degree. to 1300.degree. C. and it may be necessary to use a reduced pressure.
Processes which comprise melting involve a high energy consumption and require equipment consisting of special materials, such as stainless steel.